Spring mounting for turbogenerator stators



y 1951 M. RASHEVSKY ETAL 2,561,994

SPRING-MOUNTING FOR TURBOGENERATOR STATORS Filed Dec. 14, 1949 2 Sheets-Sheet 1 WITNESSES: INVEIETOTS a Michael Ros evs y abLFd/LA Ren A. Boudry.

ATTORNEY M. RASHEVSKY ETAL 2,561,994

SPRING-MOUNTING FOR TURBOGENERATOR STATORS Filed Dec. 14, 1949 July 24, 1951 2 Sheets-Sheet 2 INVENTORS Flg.4. Michael Roshevskya Ren A. Bcudry.

ATTORNEY Patented July 24, 1951 SPRING MOUNTING FOR, TURBO- I 'oF F ICE STATORS of Pennsylvania Application December 14, 1949; Serial-No. 132,912 I 1 Our invention relates to spring-mountings for the-stator-cores of turbine generators. improvement over the constructions shown iii-the Baudry Patent=2,320,843 of June 1, 1943;, the- Beudryand- Criner Patent 2,424,299 ofJ'uly 22, 1947. Both of these prior patents show horia zontal-shaft alternating-current dynamo-electric machines of such sizeand speed thatathedouble. frequency stator-core vibrations are large: enough. to necessitate spring-mounting. of said: core.

An object of our presentinvention. is to pro. vide a new spring-arrangement: which reduces the maximum compressive stress in any spring, thus producing ahigherfactor oi safetyagainst buckling. i Another. object: of; our; present, invention. is to provide a. novelstructural, arrangement. for se curing the two ends. of, the springs to: thecore supporting. rings and tothe outer frame-ringsirespectively.

With the foregoing. and other objects in View, our invention. consists the machines, struc tures, combinations, parts. and. methods: of design. and operation, hereinafter. described and claimed and illustrated in the accompanying drawing, wherein a Figure 1 is a transverse sectional. view of: a

machine illustratingour invention, the. sectionplane being indicated by-the; line I;-I. Fig, 2,1 Fig. 2 is aside elevationaljview; of the left half; of the machine, withthe housingrsheik broken away in longitudinal: section, so. 315-1111 expose; the. frame-construction, and. F'lgs. 3 and 4 are diagrammaticzjviewsa illustra-e tive-of'the old and new spring-mountingsystema,

respectively. i

In=.Figs.. 1 and 2,. we. havezshown. anemhodim entg at our invention in an illustrative form. of construction of aturbo-generator, which comprises astator: it and arotor; 6. The rotor. isrotatablr supported. within. the stator; prises adirect-currentfield-winding land a horizontal shaft. 8-

The. statorv Ecomprises: an. outer; frame .hl

an inner frame IL The inner frame comprisesa;

stator-core l3. which. supports. the polyphase windings M: of the. generator. The stator-core: L3. ismade up of laminations, which are stacked; 11,,

Said: rotor come.

aciaims. (Cl. 17 14252), f

It is an tensionally. supported from the outer frame l].. by two sets of four broad flat leaf-springs; S1,, S2,, S3 and S4, one set being disposed near each end; of :the machine. The flat sides of these springs are substantially tangential to the inner frame at the respective-points of. attachmentthereto, as. indicated at P1, P2, P3; and P4, and they all;ex-' tend-at an; angle: of substantially 45 to: thevertir;

' cal. The points of: attachment between the saw.

era];- springs-and the outer frame. are indicated" at. Q1, Q2,.Q3 and Q21, respectively. v pApreferre'dz structural formation. for fastene ing the respective/ends of the springs to. the;

inner and outer-frames l2. and ll is. shown. in-= Fig. 2,.-wherein..the set of. springs is shown as. being. disposed between apair of core-supporting rings I68, and 16b, andv between a pair of framerings I81; and I810, the frame-rings [8a, and [8s being spaced. further apart thanv the correspond-. ing pair of core-supporting rings 6a and its. In assembling the four broad flat leaf-springs. S1, S2, Saand'Sawe preferably first weld four; axially extending inner-frame beams B1, B2, Ba. and B4 between thepair of core-supporting rings. is and it, at the inner-frame points of attache, ment P1, P2, P 3 and P4, respectively. The outer surfaces of these beams are then accura'telymae' chined to be fiat-and substantially tangential. tlln I the inner frame, and the lower ends of there-.1

spective'leaf-springs S1, S2, S3 and Stare bolted:- to these inner-frame beams B1, B2, B3 and B4,. using bolts 2| which clamp each spring between; one of said beams and a clamping-plate 22. The

3 upper ends of the several springs S1, S2, S3 and S4 are similarly secured to four axially extending outer frame beams F1, F2, F3 and F4, which are welded in placei'or otherwise properly secured between. their frame-rings 8a and I81).

,The operation and advantages of our invention. will best beunderstood by comparison with the previously" used constructions. The spring-a1 rangementlwhich has previously been used by: the Westinghouse Electric Corporation, which is theassignee of the present application, is essen-' tially thatwhich'is' shown in the Baudr'y Patei'it" 2,320,843., as diagrammatically indicated in'our. Fig. .3; In this spring-arrangement, the entire static load or Weight of the inner frame, is carriedby two verticallsprings' SI and 32 of each.

set of iour springsl The other two springs '33; and are.disposedhorizontally, at the top and. bottom of the inner frame, respectively, so that the, thrust T/R, due ,to their share (half) .of

the rotor-torque T, is divided equally between.

the. f oursprings 3 1, 32, 33. and 34, the radius off the. pointsof attachment to the. inner frame be l ing indicated at R, Designating the static load,', orweight. of half of the inner frame, as P, thei'l compressional torces. on the four springs. 3 I., 32,,3 1i.

The spring-arrangement which was shown in the Baudry and Criner Patent 2,424,299 is similar to that which is shown in our Fig. 3, except that the springs are arranged in tension rather than compression. This tensional arrangement, shown in the Baudry and Criner patent, has not been used to any considerable extent, because of the unsymmetrical distribution of the static load on only two of the springs.

While the tension-spring arrangement of the Baudry and Criner patent has not been used, the other essential features of its structural details have been used, to the extent of using core-supporting rings (such as our rings l6) having an outer periphery 36 which is larger than the bore or inner periphery 36 of the frame-rings (corresponding to our rings l8). In this form of construction it is necessary to assemble the inner and outer rings in their proper order, before the core-supporting rods l5 are welded to the respective core-supporting rings l8, and before the housing-shell I! is welded to the frame-rings l8. Our present structural arrangement, in which a pair of core-supporting rings I68. and I61, are dis posed between a pair of corresponding outerframe-rings I85 and 18b, is new, however, and it is advantageous in enabling us to use extremely broad springs S1, S2, S3 and S4, the breadth of the springs being disposed in an axial direction and affording all of the rigidity against axial displacement, which is needed.

Our new 45 spring-arrangement, with all of the springs sharing the static load or weight P, and in tension rather than compression, is shown in our Fig. 4, by way of comparison with the old arrangement which is shown in our Fig. 3. The tensional stresses on our four springs S1, S2, S3 and S4 are as follows:

Under normal operating conditions, the torque T is small enough so that all of our springs remain under tension, but under short-circuit conditions, the torque increases some tenfold, more or less, so that two of our springs, namely S3 and S4, in each set of springs, are under a compressive force of T/(4R) -.354P. This compressive force, tending to buckle our springs S3 and S4, is considerably smaller, however, than the maximum compression-load which was placed on the spring 32 of the old arrangement of our Fig. 3, wherein the maximum compressive force was T/(4R)+.5P. This compressive force is larger than our compressive force by .854P, or over 85% of the half-weight P of the inner frame I2.

We thus have a much greater factor of safety weight-supporting springs in said frame-rings, so as to use said springs in tension, for supporting the weight P,. as distinguished from Baudrys arrangement of anchoring his weight-supporting springs 3| and 32 in the machine-foundation, rather than in, the stator frame-rings.

While we have illlustrated and described our invention in a preferred form of embodiment, we wish it to be understood that various changes can be made, in the way of substitution of details and equivalents, and by way of the addition or omission of parts. We desire, therefore, that the appended claims shall be accorded the broadest construction consistent with their language.

We claim as our invention:

1. A horizontal shaft alternating current dynamo-electric machine having anouter frame, an inner frame, a stator-core secured in the inner frame, and a plurality of sets of four flat leaf: springs for tensionally supporting the weight of the inner frame from the outer frame. the flat sides of said springs being substantially tangen tial to the inner frame at the respective points of attachment thereto. and extending at an angle of substantially to the vertical, and said machine being of such size and speed that the double-frequency stator-core vibrations are large enough to necessitate spring-mounting of said core. 1

2. The invention as defined in claim 1, characterized by said inner frame comprising. a

plurality of externally projecting core-supporting rings, and said outer frame comprisingna plurality of internally projecting frame-rings,-

each set of four leaf-springs being disposedbetween a pair of core-supporting rings and beouter-frame beams extending axially between inner frame comprising a plurality of externallyprojecting core-supporting rings, and said outer.

said pair of frame-rings, respectively.

3. A horizontal shaft alternating current dynamo-electric machine having an outer frame, an inner frame, a stator-core secured in the inner .z frame, and a plurality of sets of broad flat leafsprings connected between the inner frame and ing substantially tangential to the inner frame at,

the respective points of attachment thereto, said frame comprising a plurality of internally projecting frame-rings, each set of four leaf-springs being disposed between a pair of core-supporting rings and between a pair of frame-rings, and the fastening-means for the respective ends of said.

are large enough to necessitate spring-mounting of said core.

MICHAEL RASHEVSKY.

RENE A. BAUDRY.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 

